Article ID Journal Published Year Pages File Type
5468978 Applied Clay Science 2017 7 Pages PDF
Abstract
Due to high surface acidity and thermal stability, saponite has important applications in various fields. In this study, saponites with different Mg/Zn ratios (0-6) and a fixed Si/Al ratio of 5.43 were synthesized under hydrothermal condition. The resultant synthetic saponites were characterized by using XRD, FTIR, TG, SEM and MAS NMR. The characterization results demonstrated that, with a decrease of Mg/Zn ratio, both the crystallinity and layer stacking order of saponite were increased, and rose-like morphology was observed in Zn-saponite. Al3 + preferentially occupied tetrahedral sites in Si-O tetrahedral sheet in all synthetic saponites. A decrease of Mg/Zn ratio in octahedral sheet could improve the substitution extent of Al3 + for Si4 + and resulted in an increase of Al(IV)/Al(VI) ratio in the resultant saponite, which might be a crucial factor to control the crystal growth of saponite. The dehydroxylation temperature of saponite depended strongly on the Mg/Zn ratio and the replacement of Al3 + for Mg2 + and Zn2 + in octahedral sheets, due to their different bond strength. A 'one-to-one' mode was proposed for the substitution of Al3 + for Mg2 + and Zn2 + in octahedral sheets of the synthetic saponites.
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geochemistry and Petrology
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